1. Field of the Invention
This invention relates to percussion instrument heads such as drumheads for snare drums, bass drums, and timpanies, which are composed of synthetic resin films.
2. Description of the Related Art
In general, percussion instruments such as snare drums are made of hollow cylinders whose openings are covered with stretched skins, namely, percussion instrument heads such as drumheads. In particular, percussion instrument heads composed of synthetic resin films can be manufactured at relatively low cost and are therefore advantageous in mass production in comparison with percussion instrument heads composed of natural leathers. In addition, synthetic-resin heads are hardly influenced by environmental factors such as variations in temperature and humidity. Furthermore, they produce xe2x80x9chardxe2x80x9d sounds when beaten with drumsticks and the like.
Generally, synthetic-resin heads are each composed to one or two plies of synthetic resin films. Heads each composed of one ply of a synthetic resin film are characterized in good responses and are capable of producing sound components of higher frequencies. However, they are incapable of producing xe2x80x9csharpxe2x80x9d sounds in comparison with natural-leather heads because of the relatively long duration of sound in the tone pitch thereof. In particular, in the case of marching drums that are required to produce articulated sounds, overtones contained in sounds, which are produced by actually beating drums with drumsticks, for example, may be greatly extended in the duration thereof. In order to cope with such a disadvantage, users are required to adjust the duration of overtones by attaching mutes and the like to percussion instruments. Similar things can be said of other types of heads for use in timpani (or kettledrums) and the like, wherein overtones are extended very much in duration, which may cause unbalanced pitches (or intervals) in sound.
Heads each composed of two plies of synthetic resin films can be classified into three types as follows:
(1) Two synthetic resins are merely placed one on the other.
(2) Outer peripheries of synthetic resin films are adhered to each other by adhesive, while center portions are brought into close contact with each other.
(3) Overall areas of synthetic films are entirely adhered to each other by adhesive.
In addition, it is possible to paint patterns on surfaces of films, thus realizing variations in sound qualities in percussion instruments.
The aforementioned two-ply heads described in (1) and (2) may be capable of producing relatively sharp and articulated sounds; however, they have a problem in responses of sound components of higher frequencies. The two-ply heads described in (3) cannot produce clear differences in comparison with the conventional one-ply heads because of xe2x80x9cintensexe2x80x9d adhesion of the adhesive that is applied to synthetic resin films, wherein it is very difficult to cause positional deviations between synthetic resin films due to vibrations, which initially occur on the front-side synthetic resin film when beaten and are transmitted to the backside synthetic resin film. That is, the two-ply heads described in (3) are incapable of producing sharp sounds because of the extended duration of sound components of higher frequencies, similarly to the conventional one-ply heads.
In order to cope with the aforementioned disadvantages, Japanese Unexamined Patent Publication No. Hei 10-301560 discloses a musical instrument head and a manufacturing method therefore, wherein the musical instrument head is designed to produce sharp and articulated sounds, thus actualizing balanced pitches (or intervals) in sound. Herein, the surface of a synthetic resin sheet is polished with an emery cloth to produce roughening or irregularities thereon; then, the surface and backside of the synthetic resin sheet are coated with epoxy resins and the like, thus forming substantially planar and uniform contact surfaces. This musical instrument head has good resonating effects and can produce overtones or higher harmonic sounds having sufficiently large magnitudes in comparison with the conventional heads. In addition, this musical instrument head can be appropriately designed to simulate the exterior appearance of a natural leather because of formation of shades on the surface of the synthetic resin sheet.
According to Japanese Unexamined Patent Publication No. Hei 10-301560, the musical instrument head is manufactured in such a way that the surface of the synthetic resin sheet is mechanically polished with an emery cloth to be matted or rough (e.g., grainy or granular), which causes unexpected variations in sizes and depths of irregularities formed on the surface of the synthetic resin sheet. That is, it is very difficult to form xe2x80x9cuniformxe2x80x9d irregularities on the surface of the synthetic resin sheet. As a result, unexpected variations may occur in sound qualities of musical instrument heads, which are manufactured as described above. Thus, it is very difficult to manufacture musical instrument heads whose sound qualities are controlled and stabilized.
It is an object of the invention to provide a percussion instrument head having a rough (e.g., grainy or granular) surface on which irregularities having uniform sizes are formed by effecting chemical etching, instead of mechanical polishing, so that the percussion instrument head is capable of producing sounds of good quality.
A percussion instrument head of this invention is composed of a synthetic resin film such as a PET film having a prescribed thickness, which is subjected to chemical etching using a prescribed solution such as a caustic alkali solution, thus processing at least one surface thereof to be rough. Herein, irregularities are formed in substantially uniform sizes and dimensions on the rough surface of the film. Specifically, the solution is applied to the film in order to process a single-side surface of the film to be rough. Alternatively, the film is soaked in the solution in order to process both surfaces of the film to be rough. That is, hydrolysis processing advances firstly on surfaces of the film, which are gradually dissolved or decomposed to form irregularities, sizes and dimensions of which can be adequately controlled. After completion of chemical etching, it is possible to coat the film with an epoxy resin, for example.
Due to chemical etching in comparison with mechanical polishing, it is possible to form irregularities having substantially uniform sizes and dimensions on the surface(s) of the film for use in manufacture of the percussion instrument head, which can simulate the exterior appearance and flexibility of the conventional natural-leather head. Thus, it is possible to produce sharp and articulated sounds having balanced pitches (or intervals) when playing the percussion instrument head composed of the synthetic resin film, which can simulate the properties of the sounds of the conventional natural-leather head.